1. Field of the Invention
The present invention relates to a cutting method and apparatus for removing a jacket layer from a jacketed optical fiber.
More particularly, the present invention relates to a cutting method and apparatus by which a jacket layer of a jacketed optical fiber is safely and steadily cut in a transversal direction at a substantially right angle to the longitudinal axis of the jacketed optical fiber with a high degree of accuracy and with a high reproducibility without damaging a base optical fiber of the jacketed optical fiber.
2. Description of the Related Art
A jacketed optical fiber comprises a base optical fiber made by, for example, quartz, and a jacket layer. The jacket layer comprises a primary coating layer covering the core optical fiber, and a secondary coating layer including a buffer layer located on the primary layer.
When an end of the jacketed optical fiber is joined to another optical fiber or an optical element, the jacket layer in a terminal portion of the jacketed optical fiber must be removed.
In the removal of the jacket layer, the jacket layer in the terminal portion of the jacketed optical fiber is cut in a transversal direction at a substantially right angle to a longitudinal axis of the jacketed optical fiber, the cut terminal portion of the jacket layer is drawn out, and the remaining primary coating layer in the terminal portion is removed by dissolving or decompose-dissolving in a treating liquid. During the removal of the jacket layer, the base optical fiber must be protected from damage.
If the base optical fiber becomes damaged, even if the damage is very small and cannot be detected by microscopic observation, the damaged base optical fiber is easily broken in a bending test at a probability of 20 to 40%.
Therefore, where the damaged base optical fiber is contained as a light guide in an optical system, the resultant optical system sometimes experiences problems due to breakage of the base optical fiber and thus exhibits poor reliability for practical use.
In a conventional cutting device for cutting a jacket of a jacketed optical fiber, a terminal portion of the jacketed optical fiber is grasped at two portions thereof by a pair of clamps each having a V-shaped groove, and a pair of blades having concave half circle-shaped edges opposite to each other are applied to a portion between the grasped portions of the jacketed optical fiber to transversally cut the jacket layer into a form of an annulation. This type of conventional cutting tool is disadvantageous in that the engagement of the edges is not satisfactorily accurate, and sometimes the surface of the base optical fiber is damaged.
Accordingly, there is a strong demand for a cutting method and apparatus capable of accurately cutting the jacket layer of the jacketed optical fiber without damaging the base optical fiber.